Specimens occur in volcanic tuff becoming larger and more plentiful along the 1 mile hike to the amphitheater or exposed interior of the cinder cone, which was caused by a phreatomagmatic eruption ...

The Diamond Head cone is very symmetrical like the rim of a paper cup. Because of its very circular shape, scientists think the cone cooled off quickly after a single, highly-explosive volcanic ...

Oahu is one of the world's most beautiful destinations, but these spots take spectacular to a whole other level. Get ready to ...

The Uturuncu volcano in Bolivia, believed to be extinct for 250,000 years, shows internal signs of activity that surprise ...

Getting there: Hawaiian Airlines, Jetstar and Qantas fly from Australia to Oahu, the main gateway to all the Hawaiian islands ...

Easter Island's famous moai statues are crumbling into the sea, forcing locals to face urgent decisions about how best to protect their heritage.

The material itself is telling: volcanic tuff is deceptively fragile, porous yet resilient, tied to ancient Mediterranean civilizations.

Located 56 miles southwest of Flagstaff on the east slope of Mingus Mountain — a 1,750-million-year-old volcanic tuff — the town of Jerome and its surroundings were once known as one of the ...